slatteey



(No Model.) 7

M. M. SLATTERY.

RESISTANCE BLOCK FOR ELEOTRIG CIRCUITS.

No. 354,257. Y Patented Dec. 14, 1886.

wkg eszas. I IqY/EQ lZDI T @Mmm v J6 M t UNITED STATES- PATENT, OFFIC MARMADUKE M. M. SLATTERY, OF WVOBURN, MASSACHUSETTS, ASSIGNCR- TO THE SUN ELECTRIC LIGHT COMPANY, OF SAME'PLACE.

RESISTANCE-BLOCK FOR ELECTRIC ClRCUlTS.

SPECIFICATION forming part of Letters Patent No. 354,257, dated December 14, 1886.

Application filed October 29, 1885. Serial No. 181,228, (No model.) I

To aZZ whom it 111/014} concern: and another layer below the composition mass,

Be it known that I, MARMADUKE M. M. and then press the whole into shape. If the 40 SLATTERY, of lVoburn, county of Middlesex, shape desired be that of a cylinder, as shown, State of Massachusetts, have invented a certhe composition mass will make up the middle tain new and useful Improvement in Resistof the cylinder, as at A, and the pure carbon ance-13locks for Electric Circuits, of which the will form the ends B B; following is a full, clear, concise, and exact A greater or less resistance may be obtained 45 description, reference being had to the drawby varying the proportions of conducting and ing accompanying and forming a part hereof, non-conducting material, an increase of non 1c in which is shown a Vertical section of a conconducting material proportionately giving a venient form of my resistance-block. block of greater resistance. In this manner a The object of my invention is the producblock of any given resistance may be easily 50 tion of an economical and efficient resistance constructed. medium or block for an electric circuit; and it The block may be mounted in any suilablc 15 consists, chiefly, in the peculiar composition manner. I have shown it supplied with ter of matter, hereinafter described, of which the minal pieces or caps C D, which may be of body of the block is composed, and, further, carbon or other suitable material. 5 5 in the arrangement of this composition in the I do not desire to limit myself to the precise block between terminal layers of different method of constructing the block or trealing character, as hereinafter more fully described. the materials, as these may be varied. For en The shape of my resistance-piece is obviample, the block may be made by mixing the ouslyimmaterial. I have shown itin the form ingredients with molasses or sugar, and then 60 of a cylindrical block, A. The central porbaking or carbonizing the mass. tion of this block is composed of conducting What I claim is material mixed withnon-conducting refrac- 1. A resistance-block of conducting and tory material in varying proportions. The non-conducting materials, intimately mixed, precise ingredients are unimportant; but I combined with terminal pieces or caps of con- 6 have generally used carbon as the conducting ductingmaterial, between which the said block material, and wood ashes or plaster-of-paris is held, substantially as set forth.

0 as the non-conducting material. TheseImix 2. A resistance-block having a body conr together thoroughly in apowdered or commiposed of conducting and nonconducting manuted condition, with sufficient moisture to terials, as described, inclosed between layers 70 make them readily cohere into a mass, I of conducting material, substantially as set then make a similar mass, wholly of conductforth.

ing materialas carbon-and when I mold MARMADUKE M. M. SMT'IBRY,

the block into shape, which is done by com- Witnesses: pressing it within a mold of the proper form, \VM. A. llIAOLEOD,

I put a layer of the pure carbon mass on top, ROBERT SVALLAOE, 

